Can I test my own backflow preventer?
No. Testing requires a current backflow prevention assembly tester certification and a calibrated differential pressure gauge. Water suppliers will not accept results from an uncertified tester.
How long does a backflow test take?
Usually under an hour. Your water is shut off briefly while the tester checks each valve in the assembly with a differential pressure gauge, then the results are filed with your water supplier.
How often does a backflow preventer need to be tested?
Annually in most Maryland jurisdictions that require testing. Some suppliers allow a two-year interval for low-hazard residential devices. Your water supplier sets the schedule and often sends a reminder when a test is due.
Is backflow testing required for homeowners in Maryland?
It depends on your water supplier. COMAR 26.04.01.32 requires every Maryland water supplier to maintain an approved cross-connection control plan, and that plan sets the rules for your property. Homes with irrigation systems, boilers, fire sprinklers or a well alongside municipal water are the most commonly affected.